M38 Rear Main Oil Seal
Posted: Sat Jul 04, 2020 3:27 pm
I asked this question over on the M38 boards on the G boards but I figured I would ask it here to get the most valuable response.
I recently installed an engine that I had built about 12 years ago in an M38. This engine had only about 10 miles on it since rebuild and ran like a top. I pre-lubed (oil pump with teeth ground off) the engine before I cranked it. The engine seized up after just a few miles. Suspecting the rear main oil seal, I pulled the engine and removed the crankshaft, I noticed the rear mail oil seal was the dreaded Victor oil seal. Took the crankshaft to the our local machine shop and had it turned.
I ordered a new oil seal from one of the Military parts dealer in the Midwest. The oil seal that they sent was a "Best Gasket 3B71" and they said I shouldn't have a problem with the oil seal causing another crankshaft seizing problem. Well, I installed the oil seal according to the M38 & M38A1 books, buttoned the engine back up and installed it in the jeep. I ran the jeep for about 6 miles and pulled the jeep back into the shop and noticed that I now have a small oil puddle under the jeep. Apparently the new rear main oil seal is leaking. I am going to pull the engine back out and put another oil seal in.
What brand of rear main oil seal should I use? Please don't say that you would 40 year NOS seals, cause not everyone has access to a NOS supply.
Not wanting too but I'm thinking of going old school and installing a rope seal.
If you were rebuilding an M38 engine now, what oil seal would you use? Comments welcomed & appreciated.
I recently installed an engine that I had built about 12 years ago in an M38. This engine had only about 10 miles on it since rebuild and ran like a top. I pre-lubed (oil pump with teeth ground off) the engine before I cranked it. The engine seized up after just a few miles. Suspecting the rear main oil seal, I pulled the engine and removed the crankshaft, I noticed the rear mail oil seal was the dreaded Victor oil seal. Took the crankshaft to the our local machine shop and had it turned.
I ordered a new oil seal from one of the Military parts dealer in the Midwest. The oil seal that they sent was a "Best Gasket 3B71" and they said I shouldn't have a problem with the oil seal causing another crankshaft seizing problem. Well, I installed the oil seal according to the M38 & M38A1 books, buttoned the engine back up and installed it in the jeep. I ran the jeep for about 6 miles and pulled the jeep back into the shop and noticed that I now have a small oil puddle under the jeep. Apparently the new rear main oil seal is leaking. I am going to pull the engine back out and put another oil seal in.
What brand of rear main oil seal should I use? Please don't say that you would 40 year NOS seals, cause not everyone has access to a NOS supply.
Not wanting too but I'm thinking of going old school and installing a rope seal.
If you were rebuilding an M38 engine now, what oil seal would you use? Comments welcomed & appreciated.
